This invention relates to readers for code punched cards and more particularly to readers employing light to read the code punched card.
There are many such code punched card readers in the prior art. For instance, one such reader would include a light emitting device and light detecting device for each of the code bit areas of the code punched card. The disadvantage of such a reader is that a large number of light emitting devices and light detecting devices are required to read the coded information on the punched card.
Another type of reader for a code punched card, as disclosed in U.S. Pat. No. 3,341,692, includes a plurality of sandwiched optically coupled paneled sections arranged in cooperative electrical relation. The sections primarily comprise a suitable light source, such as any well known electroluminescent phosphor embedded panel, an information coded element, such as a matrix or mask, a first series of parallel closely spaced transparent electrical conductors extending in the X-axis direction, a photoconductive panel, and a second series of parallel closely spaced electrical conductors extending in the Y-axis direction.
A disadvantage of this arrangement is that the light source to read the code punched card is the utilization of electroluminescent phosphor embedded panel coextensive with the code punched card emitting light from its entire surface and having no photodetectors.